Polyamide-epoxy resin reaction product



United States Patent POLYAMIDErEBOXY RESKN REACTION PRODUCT Don E. Floyd, Robbinsdale, Minn., assignor to General Mills, lnc.,, a corporation of Delaware No Drawing. Application July 15, 1953 Serial Not 368,217

6 Claims. (Cl; 26018) The presentinvention. relates to the reaction products of certain polyamides derived from polymeric fat acids and-epoxy resins.

In the copending application of Malcolm M. Renfrew and Harold Wittcoff, Serial No. 276,054, filed March 11,

1952, now Patent 2,705,223, there are disclosed the. reaction products of certain polyamide resins derived.

from polymeric fat acids with epoxy resins. These compositions are shown to possess unusual and desirable properties.

flexibility such that the products are not brittle.

It has now been found that by employing polyamide resins made from mixtures of polymeric fat acids and dimerized rosin, the cured compositions obtained from thesepol'yamide resins. with epoxy resins have. greater hardness, improved compatibility and more rapid dry to. the tack free stage.

It. is, therefore, an. object. ofthe present invention to 1 presence of-caustic alkaliwhich is usually employed in at least the quantity-necessary to combine with the halogen liberated from-the halohydrin, and .usually. is em ployed in excess. terminal. epoxygroups-or. terminal epoxygroups and terminal primary hydroxyl groups. In. the. complex reac-. tion mixture the terminal epoxy groups are generally in excess of the terminal primary hydroxyl groups. Typical polyhydric phenols include resorcinol, and various bisphenols resulting from the condensation of phenol. with aldehydes and ketones such as formaldehyde, acetalde- I;

hyde, acetone, methyl ethyl ketone and the like. Resins of this type are disclosedin Greenlee Patent 2,585,115 and these resins are useful in the present invention.

The molecular weight of the epoxy resins-may be con.- trolled by the relative proportions .of the reactants, as. well as by the extent to which the reaction is carried on. The present invention involving the curing of these epoxy resins may be appliedto all epoxy. resins... The molecular weight of the resin. is not critical since both very low molecular weight resins, as well as very high molecular weight resins, can. be.- cured by this method. The;properties of thecured resin compositions may, of course, vary with the molecularweightof the. epoxy resinernployed, as well as the nature and molecular weight of the polyamide employed.

The poly-amides which may be usedv with these epoxy The. products. obtained may contain The reaction product is a hard, infusible, I insoluble, resinous material with a desirable degreeof triamine,

. 2,823,189- Patented. Feb. 11., 1.958

resinsare those derivedfroma mixture of polymeric fat acids and. dimerized rosin with polyalkylene polyamines. The. polymeric. fat acids. employed. in preparing the polyamides are those resulting from the polymerization of drying or semi-dryingoilsor from the free acids or simple aliphatic, alcoholesters of such acids. or semi-drying oils include soybean, linseed,,tung, perilla, oiticica, cottonseed, corn; tall, sunflower, safllower, dehydrated castor. oil andthe like. In thev polymerization procession the preparation of. the polymeric fat acids, the fatty acids. With. suflicientv double bond functionality combine, for the. most part probably bya- Diels-Adler mechanism, to. provide a.-mixture of dibasic and higher polymeric. acids- The acids with insufficient functionality to reactremain.asmionomersr and may be Wholly or partially removed, for example. by; distillation. Thev residue after distillation: consists of the desired polymeric. acids and thismixt-ure is.used..for, the. preparation of the polyamideresin. Inplace; of this, method ofpolymerization, any other method of polymerization may be employed Whether the resultant polymer possesses residual unsaturation or not. The term polymeric fat acids as used herein; is; intendedtto; include the; polymerized. mixture of acids employed, which mixture usually. contains a predominant portion of dimeric acids, a smaller quantity of trimeric and higher polymeric acids, and some residual monomer. The amount; of monomer which the product contains may be variedto produce a variety of products. The monomer tends to. restrict the size of the polyamide obtainedand"frequently it is desirable to employ a substantial; quantity of. monomer such that a liquid or at least ,flowable polyamide: product is obtained.

These; poiymeric fat acids .may: be reacted with a variety;ofi'polyalkylenepolyamines for the production of the polyamide. Suitable polyamines include diethylene triethylene tetramine, 3',3"-imino-bis-propylamine, and 'similarpolya'lkylene polyamines. The amidification reaction may'be carriedout under the. usual conditions employed for this purpose; Polyamides of this type generally have molecular weights varying from 1,000l0 ,0'00 and are resistant to the corrosive action of Water, alkali, acids, oils, greases and organic solvents. The melting points vary depending upon the reactants and the; reaction conditions. Low. melting polyamide resins melting, Within the approximate, range of. 2590 C. are preferred; Higher oralowermeltingpoints. are also suitable for the present invention.

The dimerized rosin employed is essentially a dimeric rosin acid. This type of material is available under the trade names of Dymerex Resin (Hercules Powder Co.) and Dimer (Newport Industries). Considerable variation is possible in the. amount of dimerized rosin which is employed; Some improvement in hardness, compatibility and drying properties are observed even with the small quantities of, for example, 0.05 equivalents-perequivalent; ofpolymeric; fat acids. The quantity of rosin dimer should not exceed 1 equivalent per equivalent of polymeric fat acids, otherwise there is a tendencyfor'the mixed polyamides and epoxy resins to become brittle when cured. The polyamides should have an amine number within the range of 20-250. By amine number is intended the number of milligrams of potassium hydroxide equivalent to the free amine groups in one gram of resin. The reaction with the epoxy resin occurs through. the. amine. group and accordingly with amine numbers lower than 20 there is a tendency toward low reactivity. On the other hand when amine numbers exceed 25,0, there, is a tendency for some odor totlienprQdlilctrand some volatility resultingin loss of Suitable dryingcentrations. Thus, quantities of from 2-5% of the polyamides based on the weight of the polyamide-epoxy resin mixture are eifective as flow additives for epoxy resins. Generally, however, it is preferred to employ larger concentrations of the polyamide, especially from 20-80% of the polyamide based on the combined weights of the resins.

The mixed resins may be obtained by blending separate solutions of the resins in suitable solvents. The polyamides are soluble in aromatic hydrocarbons such as toluene admixed with aliphatic alcohols such as isopropanol, n-butanol and the like. The epoxy resins are soluble principally in ketone solvents. The two resins may be separately dissolved and the solutions mixed to obtain a composition which may be cured. The solutions may be prepared at reduced temperature, room temperature, or elevated temperature, and the mixed compositions may be cured at room temperature or above. It is also possible to prepare mixed resins without the employment of solvents by simply mixing the resins and fusing them. The mixed resins, either by themselves or in the form of solutions, may be applied by molding, pouring, dipping, brushing, casting or spraying.

EXAMPLE 1 A polyamide was prepared by heating together the following ingredients:

G. Polymeric fat acids (0.75 equivalent) 217 Dimerized rosin-Dimer 120 (0.25 equivalent) 97 Distilled cottonseed-type fatty acids (0.06 equiv.) 18.8 Diethylene triamine, 98% pure (1.56 equiva1ent) 54.6

The reaction mixture was heated to 200 C. and stirred for three hours. Vacuum was applied to the system during the last hour. The product was removed from the reaction vessel and cooled. It had the following properties:

Ball and ring melting point 73 C.

Acid number 34.1.

Amine number 86.8.

Viscosity (35% solution in 1:1

butanolztoluene) A2 Gardner- Holdt.

Color 11-12 Gardner This resin was found to give thermoset, cured products in combination with epoxy resins, as illustrated below.

Coating formulations were prepared by mixing together solutions of the polyamide (at 50% solids in equal parts of isopropanol and toluene) with various epoxy resin solutions (at 50% solids in equal parts of methyl ethyl ketone and toluene.) Films were cast on glass and tin panels with a 1% mil blade. The properties are tabulated below.

Air dry films Rocker Hardness Composition (by wt.)

1 day 4 days 7 days Epon 834 {58 golyanhlle 17 41 47 5 pen 1 Eolyamgide 38 61 p0118 ts 5 S pon 4. %,0 1 21 so so pon 1 {70 Polyamide 44 45 Baked films (at 300 F. for 20 minutes) Composition (by wt.) HRogler ar ess 50 Epon 834 {50 Polyamide 59 2 {50 Epon 1001 63 golyaggidan pon ts pon {30 Polyamide 73 5 30 Epon 1001 57 70 Polyamide EXAMPLE 2 .A polyamide was prepared, following the procedure outlined in Example 1, from the following ingredients:

1 G. Polymeric fat acids 225 Dimerized rosin-Dimer 120 100.5 Distilled cottonseed-type fatty acids 265.5 Diethylene triamine 88.5

The product was a viscous, resinous liquid. The properties of the resin were found to be as follows:

A mixture of a portion of this polyamide and an equal amount of Epon 834 was prepared by stirring the two materials together at room temperature. On curing at 125 C. overnight a compatible, hard, resilient, thermoset resin body was obtained.

EXAMPLE 3 A polyamide was prepared as in Example 2 from the following ingredients:

G. Polymeric fat acids 225 Dimerized rosinDymerex resin Distilled cottonseed-type fatty acids 255.5 Diethylene triamine 88.5

The product was a viscous, resinous liquid, having the following properties:

Acid number 22.6. Amine number 70.4. Viscosity (35% solution in 1:1

butanolztoluene solution) A4A5 (Gardner- Holdt). Color 10-11 Gardner 1933.

A mixture of a portion of this polyamide and an equal amount of Epon 834 was prepared by stirring the two materials together at room temperature. On curing at 125 C. overnight a compatible, hard, resilient, thermoset resin body was obtained.

EXAMPLE 4 A polyarnide was prepared by heating together the fol- 5 lowing ingredients:

G. Polymeric fat acids (0.75 equivalent) 217 Dimerized rosinDimer 120 (0.25 equivalent) 97 Triethylene tetramine (2.65 equivalent) 96.8 The reaction mixture was heated to 200 C. and stirred for three hours. Vacuum was applied to the system during the last hour. The product was removed from the reaction vessel and cooled. It had the following properties:

Ball and ring melting point 64.7 C. Acid number 31.4. Amine number 175.0. Viscosity solution in 1:1 20

butanol:toluene solution) A2-A3 Gardner- Holdt.

Color 11-12 Gardner 1933.

Coating formulations were prepared and tested as in Example 1. 2

Air dry films Baked films (at 300 F. for 20 minutes) Rocker Composition Hardness Polyamiden 2 30 Epon 1001 70 Polyamide a 70 Epon 1001 4 {50 Epon 1007 Polyamtde {30 Epon 1007 1' E50 Epon 1001 Polyamide 6 70 Epon 1007 30 Polyamide 6 The resins known to the trade as Epon 828, Epon 834, Epon 1001, and Epon 1007 are made from bisphenol A and epichlorhydrin and have the following characteristics:

Melting Ool0r Viscosity, Epoxide Point, Gardner Gardner- Equivalent 0. 1933 Holdt Epon 828 8- 12 12 max. Z5-Z6-l- 210 Epon 834.- 20- 28 l 10 max AZ-Al 225 290 Epon 1001. 64- 76 1 8 max C-G 450- 525 Epon 1007 127-133 1 8 max Y-Z 1, 660-2, 000

40% solutions in Butyl Carbitol.

5 merized rosin is employed in a concentration of from .05-1

equivalent per equivalent of polymeric fat acids.

3. Composition according to claim 1 in which the polyamide has an amine number of from 20250.

4. Composition according to claim 1 in which the polyalkylene polyamine employed is diethylene triamine.

5. Composition according to claim 1 in which the polyalkylene polyamine employed is triethylene tetramine.

6. Composition of matter comprising an epoxy resinous material containing terminal epoxy groups derived from a polyhydric phenol and epichlorohydrin and having an epoxide equivalency in the range of 190 to 2000, and a polymeric polyamide derived from diethylene triarnine and a mixture of polymeric fat acids and dimerized rosin, the dimerized rosin being employed in the ratio of from .051 equivalent per equivalent of dimerized polymeric fat acid, the polyamide having an amine number of from 20-250 and being employed in the ratio of from 280% based on the combined weights of the resins.

Cowan Oct. 28, 1948 Greenlee Mar. 18, 1952 

1. COMPOSITION OF MATTER COMPRISING AN EPOXY RESINOUS MATERIAL CONTAINING TERMINAL EPOXY GROUPS DERIVED FROM A POLYHYRIC PHENOL AND EPICHLOROHYDRIN AND HAVING AN EPOXIDE EQUIVALENCY IN THE RANGE OF 190 TO 2000, AND A POLYMERIC POLYAMIDE DERIVED FROM A MIXTURE OF POLYMERIC FAT ACIDS AND DIMERIZED ROSIN AND A POLYALKYLENE POLYAMINE SAID POLYAMIDE CONTTAINING FREE AMINE GROUPS. 